Grinding-machine.



J. H. LETZ.

GRINDING MACHINE.

APPLICATION FILED APR. I7. 1915.

Patented Apr. 24, 1917.

4 SHEETS-SHEET l.

J. H. LETZ.

GRINDING MACHINE.

APPLICATION FILED APR. 17, 1915.

1,223,497. Patented Apr. 24, 1917.

4 SHEETS-SHEET 2.

J. H. LETZ.

GRINDING MACHINE.

APPLICATION FILED APR. 11. 1915.

Patented Apr. 24, 1917.

4 SHEETS-SHEET 3.

J. H. LETZ.

GRINDING MACHINE.

APPLICATION FILED APR. 17. I915. 1,223,497. I

' Patented Apr. 24, 1917.

4 SHEETS-SHEET 4.

UNITED STATES PATENT OFFICE.

JOHN HOLIIAND LETZ, 0F CROWN I POINT, INDIANA, ASSIGNOR TO THE LETZ MANUFAC- TURING COMPANY, OF CROWN POINT, INDIANA, A CORPORATION OF INDIANA.

GRINDING-MACHINE Specification of Letters Patent.

Patented Apr. 24, 1917.

' Application filed April 17, 1915. Serial No. 21,941.

same by making it more efiicient in opera-' tion and cheaper to construct.

In the use of the grinding machine shown in the aforesaid patent, while it was eflicient for most kinds of grinding, I found that it would not grind jerked corn, 2'. 6., ear corn that had been pulled off of the stalks without removing the husks, because the husks wound around the shaft and accumulated in the open space between the burs and. the shaft. With my present construction, this space is done away with and feeding means are provided to carry the husks positively from the adjacent end of the concave out to the grinding face of the curve.

Other features of my invention are concerned with novel structural combinations by which the machine can be more cheaply manufactured by reducing the amount of material contained therein and making the combinations easier to assemble.

To illustrate my invention, I annex hereto four sheets of drawings, in which the same reference characters are used to designate identical parts in all the figures, of which,

Figurel is a top plan view of the complete machine, with the hopper in section;

Fig. 2 is a central vertical section through the bur-casing and one end of the shaft, on a larger scale than is shown in Fig. 1;

Fig. 3 is a view, as seen in section on the line AA of Fig. 2;

Fig. 4 is a view as seen in section on the line B-B of Fig. 2;

Fig. 5 is a view as seen in section from the right-hand side of Fig. 2, but with the right-hand side of the bur-casing and the stationary bur removed;

Fig. 6 is a fragmentary view, as might be seen in section on the line O-C of Fig. 3;

Fig. 7 (Sheet 1) is a view in section as if seen from the left-hand side of Fig. 2, but

with the corresponding side of the burcasing and the rotating bur removed;

Fig. 8 is a perspective view of the feeding collar secured on the shaft at the end of the concave adjacent to the bur-casing;

Fig. 9 is an end view of the machine as seen from the left-hand side of Fig. 1;

Fig. 1 0 is a detail on a scale still larger than Figs. 2 to 8, showing the connections between the concave and the bur-casing;

Fig. 11 is a view on the same scale as Fig.

- 10, as seen in section on the line DD of Fig. 9;

Fig. 12 is a detail, as seen in section on the line E-E of Fig. 11; and

Fig. 13 is a perspective View of the cam lever cooperating with the bearing yoke casting.

As in my prior Patent No. 1,077,714, the

grinding concave 20 has its bottom provided with the crushing ribs 30, and is supported by the legs 25 secured to the ears 24 formed on the outer lower corners of the concave. Journaled in the bearing 26 secured on-the outer end of the concave is the shaft 27, the other end of which is journaled in bearings to be subsequently described. This shaft 27 has rigidly secured thereon, as by the pin 33, the sleeves 32, which have the spiral crushing and feeding ribs 31 formed thereon, and cooperating with the ribs 30 to crush the ears and cobs placed in the hopper 23 and to feed them on to the bur-casing, which is made up of the cylindrical portion 28 and the convex portion 29. The concave is provided with ears 35 projecting upwardly from the end adjacent the bur-casing member 28, and these cars 35 are provided with apertures which are in alinement with apertures formed in the rear of the bur-casing member 28, which member is preferably provided with hollow, rectangular projections 36, which register with similar hollow, rectangular projections 37 formed on the adjacent portions of the burcasing member 29, which is also provided with apertures in the projections 37, so that the threaded rods 38 may extend through apertures in all three members, and by tightening up the nuts 39 and 40, these three members may be securely clamped together. The outer face of the bur-casing member 29 is provided with the concave bearing recess 41, with which cooperates the ear 42 having its adjacent face convex to cotiperate with the concave bearing surface, both bearing faces having apertures therethrough, through which may be passed the short bolt 43, so that by screwing up the nuts 44, the bearing bracket 45, of which the ear 42 constitutes a part, may be secured on the bur-casing at any desired angle that may be necessary to properly aline the shaft 27 in the bearings 46 and 47 supported on the bracket 45, which, where two of these bearings 46 and 47 are employed, preferably is U-shaped to accommodate the pulley 48, which may be secured on the shaft between said bearings.

To adjust the position of the shaft 27 long itudinally, and thus determine the distance between the bur-faces to be described, I provide the yoke 49, which preferably has the main portion 50 thereof of the general shape of a semicircle and T-shaped in cross section, as seen in Fig. 2. The horizontal rib enters the recess 51 in the end of the sleeve-like bearing-cup 52, which is longitudinally movable in the bearing 47, and preferably has the hard-metal bearing-disk 53 therein, against which rests the bearing ball 54, which in turn engages the hardened bearing disk 55 mounted in the end of the cup 52 and engaging the adjacent end of the shaft 27. The yoke 49 preferably has the connecting bar 56, which rests on the bearing 46 when the parts are assembled, and extended out from the side of the yoke beyond the connecting bar 56 are the ears 57, through which the extended ends of the threaded rods 38pass. It will be obvious that the position of the yoke 49 on these rods 38 will control the longitudinal position of the shaft 27, and for this purpose I thread the nut and lock nut 58 on one of the rods 38, and on the other rod I employ the nut,59 and lock nut 60, which nuts preferably take the form of hand wheels for ready adjustment, but instead of having these coiiperate directly with the ear 57, 1 preferably interpose the helically-coiled expanding spring 61 and the cam lever 62, which is provided with cam flanges 63 and 64, which are adapted to cooperate with the rib surfaces 65 and 66 formed on the adjacent ear 57 as best seen in Figs. 12 and 13. A stop lug 67 also cotiperates with the rib 65 to limit the movement to the position in which the tension is entirely released. When it is desired to tighten up the parts, the cam lever is turned clockwise to bring the high portions of the cam flanges 63 and 64 upon the ribs 65 and 66. By this mechanism, it will be seen that I secure a ready and effectwo control of the longitudinal position of the shaft 27 and thus the distance between the grinding faces of the burs.

The shaft 27 has pinned or otherwise rigidly secured thereonthe supporting disk 68, t0 the outer periphery of which is bolted the flat grinding annulus 69, which, as will be seen, consists of the flat surface having the ribs 70 raised slightly above said surface and ground ofi' flat. Opposed to this flat annular bur is a stationary bur 71, seen in Fig. 7, the portion of which opposed to the bur 69 is of the same design and construction. vThis bur is bolted to the trammeling disk 72, seen' in rear elevation in Fig. 3, which disk is provided with the vertical bearing ears 74 and 75, in which are secured the pins 76, which are journaled in bearings formed in the ears 77 and 78 of the trammeling annulus 79, which has the two lugs 80 and 81 on its periphery, fitting into the recesses 82 and 83 formed in the inner face of the periphery of the bur-casing member 28. With the construction shown, it will be obvious that the stationary bur 71 can move as. may be necessary to accommodate itself to the position of the rotating bur 69, as is customary in this class of machines. The trammeling disk 72 is provided on its rear inner periphery with the flange 85, which fits into an annular channel formed on the inner face of the bur-casing member 28, a suitable packing 86 being interposed between the flange and the bottom of the channel. The central aperture of member 28 has a plurality, preferably four, of teeth 87 projecting inward and adapted to cotiperate with ribs on the feeding cone 88, which is bolted to the supporting disk 68 within the bur-annulus 69, as clearly shown in Fig. 2. This feeding cone is of a generally conical shape except that the surface is concave, as seen in Fig. 2, and has the four sets of teeth 89, 90, 91 and 92 projecting inwardly therefrom, the teeth increasing in length and forming a generally spiral effect, and cooperating with the sets of teeth 93 and 94 formed on the inner portion of the stationary bur 71. By reference to Fig. 2, it will be seen that the outline of the teeth 93 and 94 diverges slightly from the outline of the teeth 89 to 92, so that a gradually contracting annular passage is formed leading outwardly to the flat grinding faces of the burs 69 and 71. The feeding cone 88 extends to and preferably through the outer wall of the member 28 of the bur-casing and abuts against the feeding collar 95 secured on the shaft 27 between the adjacent sleeve 32 and said feeding cone. This collar 95 is provided with the two teeth 96, which form a continuation of the feeding ribs 31, so that the corn in the concave will be crushed and fed to the contracted annular feeding aperture and carried out through the passage, the teeth of which serve to further break up the corn, until it reaches the annular grinding faces 69 and 71, which serve to grlnd up the corn to the desired fineness. The construction shown takes care of the husks and prevents their winding about and accumulating on any portion of the feeding mechanism, with the result that it is impossible to clog the machine with jerked corn, which is not the fact with the machine of the prior Patent No. 1,077 ,7 l4, and similar machines known to me.

Suitable means must be provided for regulatin the feed, and for this purpose I form in the outer face of the bur-casing member 28 a shallow, flat channel 97 above the shaft 27 and a similar channel 98 below the shaft, and in each of these channels I mount a sliding shut-off plate 99 and 100, which plates have the customary q semicircular recess in the bottom to coopcrate with the periphery of the collar 95, or with the adjacent end of the feeding cone 88, depending upon the exact position of the shaft. These feeding plates have vertical slots 101' therein, through which are passed bolts and nuts 102 to secure them in any desired position of adjustment. To conveniently secure the hopper 23 in place and prevent its possible separation from the adjacent face of the bur-casing 28, I provide the concave with a pair of lugs 103 and 104 projecting up from its surface in suitable proximity to the adjacent face of the bur-casing member 28, so that when the sheet-metal hopper 23 is shoved down in place, it will be tightly wedged between the adjacent wall of the bur-casing and the lugs 103 and 104.

While I have shown and described my invention as embodied in the form which I at present consider best adapted to carry out its purposes, it will be understood that it is capable of some modification, and that I do not desire to be limited in the interpretation of the following claims except as may be necessitated by the state of the prior art.

What I claim as new, and desire to secure by Letters Patent of the United States,'is:

1. In a grinding machine, the combination with a cylindrical concave provided with crushing ribs, of a hopper located above the concave and discharging thereinto, a bur casing at one end thereof, a shaft extending through said concave and casing and provided in the concave with a sleeve carryin'g'crushing and feeding ribs cooperating with ribs on the concave, a bur secured to the shaft within the casing and having a flat annular grinding surface at its periphery and a conical central portion projecting from said grinding surface to the adjacent end of the concave and abutting the sleeve and provided with feeding ribs on its surface, a stationary bur secured to the bur-casing and having a corresponding flat annular grinding surface at its periphcry and a hollow conical central portion provided with feeding ribs cooperating with the ribs of the rotating bur, the two sets of conical ribs converging as they approach the grinding surfaces, and means for controlling the rate at which the material to be ground is delivered from the concave to the burs.

2. In a grinding machine, the combination with a frame, of a bur-casing secured thereto having a bearing concavity therein, a stationary bur mounted in the casing, a shaft passing through the bur-casing, a rotating bur carried thereby, a bearing bracket having a convex bearing cooperating with the aforesaid concavity, a bolt passed through the bur-casing and the convex hearing to secure the bearing bracket to the casing, and means supported from the frame and casing and cooperating with the shaft to determine the relative position of the burs.

3. In a grinding machine, the combination with a concave having ears with apertures therein, of a bur-casing having apertures therein in alinement with the apertures in the concave and having a bearing concavity therein on the side opposite the concave, a stationary bur mounted in the bur-casing, a shaft passing through the burcasing and having a rotating bur secured thereto, a bearing on the concave for the shaft, a bearing bracket having a convex bearing-surface cooperating with the aforesaid concavity in the bur-casing, a bolt passed through the bur-casing and convex bearing-surface to secure the bearingbracket to the casing, a yoke cooperating with the bearing attached to the bur-casing to control the distancebetween the burs and having ears with apertures therein, a pair of threaded rods extending through the apertures of the concave, bur-casing and yoke, and securing means cooperating with the threaded rods to lock the bur-casing to the concave and to determine the position of the yoke relative to the bur-casing.

4-. In a grinding machine, the combination with a concave havlng a pair of lugs extending upwardly fromone end thereof, a burcasing bolted to the end of the concave adjacent to the lugs, anda hopper resting on the concave and having one end adapted to pass between the lugs and the adjacent end of the bur-casing and to be held in position thereby, so that it can be lifted off when desired without otherwise disassembling the machine.

5. In a grinding machine, the combination with a concave having a pair of lugs extending upwardly from one end thereof, a bur-casing bolted to the end of the concave adjacent the lugs, a hopper resting on the concave and having one end adapted to pass between the lugs and the adjacent end of the bur-casing and to be held in position thereby, so that it can be lifted off when desired without otherwise disassembling the machine, a shaft journaled in the concave and passing through the bur-casing, a rotating bur secured to the shaft, a stationary bur mounted in the bur-casing, and a feed-controlling plate adjustably mounted between the hopper and the adjacent side of the bur-casing.

6. In a grinding machine, the combination with a bur-casing, of a shaft extending therethrough, a supporting disk secured thereto, a flat grinding annulus secured to the periphery of the disk, a feeding cone with ribs on its generally bell-shaped surface'secured to the disk within the annulus and extending to the receiving aperture of the casing, a stationary bur having a fiat peripheral grinding portion cooperating with the annulus, and a central ribbed concave portion cooperating with thefeeding cone to form an annular feeding passage that narrows in cross section from the receiving aperture to the annular rinding faces, and connections between the with a bur-casing having an annular receiving aperture with inwardly directed teeth on the edge thereof, of a shaft extending therethrough, a supporting disk secured thereto, a flat grinding annulus secured to the periphery of the disk, a feeding cone with ribs on its generally bell-shaped surface secured to the disk within the annulus and extend-- ing to the receiving aperture of the casing, a stationary bur having a flat peripheral grinding portion coiiperating with the annulus and a central ribbed concave portion which together with the, teeth of the receiving aperture cooperate with the feeding cone to form an annular feeding passage that narrows in cross section from the receiving ape-r- I casing at one end thereof, a shaft extending through said concave and casing and provided in the concave with a sleeve carrying crushing and feeding ribs cooperating with ack of the bur-casing and the stationary bur permitting the;

the ribs on the concave, a bur secured to the shaft within the casing and having a flat annular grinding surface at its periphery and a conical central portion projecting from said grinding surface to the adjacent end of the concave and abutting the sleeve and provided with spiral-shaped feeding ribs on its surface designed to screw the material to the flat annular grinding surface, a stationary bur secured to the bur-casing and having a corresponding flat annular grinding surface at its periphery and a hollow conical central portion provided with spiralshaped feeding ribs cooperating with the ribs of the rotating bur to screw the material to the flat annular grinding surface, the two sets of conical ribs converging as they approach said grinding surfaces, and'means for controlling the rate at which the material to be ground is delivered from the concave to the burs.

9. In a grinding machine, the combination With a cylindrical concave, of a hopper located above the concave and discharging freely thereinto, a bur-casing at the end of the concave, a shaft extending through said concave and casing, a sleeve on the shaft within the casing, feeding ribs on the sleeve to force material from the concave to the casing, a bur secured to the shaft within the casing having a peripheral grinding portion and a conical central portion projecting therefrom, feeding ribs on the surface of the central portion which extends to the adjacent end of the concave and abuts against the end of the aforesaid sleeve which at the point of contact has the same diameter as the end of the conical central portion, a stationary bur secured to the bur-casing and having a peripheral grinding surface and a hollow conical ribbed central portion cooperating with the ribs of the rotating bur, the two sets of conical ribs converging as they approach the peripheral grinding portion, and a movable feed-controlling plate cooperating with the end of the conical central portion and the sleeve between the ribs thereon to control the rate at which the material to be ground is delivered from the concave to the burs.

In,witness whereof, I have hereunto 'set my hand and afiixed my seal this 6th day of April A. D. 1915.

JOHN HOLLAND LETZ. [1 s] 

